I think about this sometimes, and I think it ultimately comes down to how society acts as a whole, which is mostly out of our direct control. Society can use any tool for good or evil; just as a knife can cut bread or hurt a person, so too can Apache serve Wikipedia or serve the MPAA/RIAA's intranet.
There's definitely a cutoff point (if you're designing a nuclear-tipped rocket, there's usually just one reason for that) but stressing about whether or not the general-purpose software we create will be used for evil will only frustrate the cause of good.
What if your nuclear arms are never meant to actually be used, but the implicit threat of having that capability will keep your country from being bullied by other countries?
Not even nuclear weapons are entirely black-and-white.
A nuclear tipped rocket is indeed not a great example.
On the other hand, say you had someone with a passion for rocketry and space, who found that the best way to pursue their dreams at the time was to build conventional bomb tipped rockets with slave labor...
Still not exactly black and white, but a good deal less fuzzy I think.
Playing chicken with the world in order to prevent another conventional war between two superpowers... justified.
Otherwise, a hardline faction in any government could have easily pushed for it. Not the mainstream political force in the USA, most probably. (Though, who really knows, looking at Vietnam.) Also, my understanding is that the USSR was in an echo chamber that led it to believe capitalist USA would collapse on itself (hence the "we will bury you" line), so probably they wouldn't have attacked neither. Though the USSR had clearly the edge in a ground war, and I'm sure plenty fanatics could have been found. So there was still that possibility.
Of course, the perfect solution would be a perfectly-balanced economic/political federation of countries, policed by a neutral organization. That couldn't happen then, and that won't happen in the future. Neither Western countries, nor China+Russia, nor specially Arabic countries, will submit to a UN decision that violates their core political tenets, be it justified or not.
You seem to imply that "a little bit of negotiating leverage" is of trivial consequence rather than a question of how many people were at the mercy of a corrupt and perversely-incentivized bureaucrat or an abusive factory owner.
We didn't fight the cold war over which side you butter your bread on.
There's definitely a cutoff point (if you're designing a nuclear-tipped rocket, there's usually just one reason for that) but stressing about whether or not the general-purpose software we create will be used for evil will only frustrate the cause of good.